This invention relates to novel compounds which are useful as topical antimicrobial agents and more particularly to antimicrobial compounds which are absorbed to teeth, and which are effective against the microorganisms that produce dental plaque.
Dental plaque is a soft, tenacious bacterial deposit which forms on the surface of the teeth. It is produced by the action of certain bacteria viz., S. mutans, A. viscosus, and A. naeslundi, on carbohydrate substances in the mouth. Of the numerous antimicrobial agents that have been investigated for their ability to inhibit plaque formation, only 1,6-bis(p-chlorophenylbiguanidino)hexne (chlorhexidine) and 1,6-bis(2-ethylhexylbiguanidino)hexane (alexidine) are reported to be clinically effective antiplaque agents. However, because these agents are extremely strong organic bases, and consequently are almost entirely cationic at the prevailing pH of the mouth, they suffer from the following disadvantages: (1) they are preferentially adsorbed to the oral mucosa rather than to the teeth, (2) they are extremely bitter-tasting substances, (3) they produce local irritation of the oral mucosa and tongue, (4) when swallowed they are adsorbed to the gastrointestinal mucosa.